Effect of pheromone trap density on mass trapping of male potato tuber moth Phthorimaea operculella (zeller) (lepidoptera: gelechiidae), and level of damage on potato tubers

Potato tuber moth (PTM), Phthorimaea operculella (Zeller), is one of the pests that cause the most damage to potatoes ( Solanum tuberosum L.) in both field crops and storage, especially in regions where summers are hot and dry. Larvae develop in the foliage and tubers of potatoes and cause direct losses of edible product. The use of synthetic pheromones that interfere with insect mating for pest control has been widely demonstrated in numerous Lepidoptera and other insect species. An experiment was carried out during the 2004-2005 season in Valle del Elqui, Coquimbo Region, Chile, to evaluate the effectiveness of different pheromone trap densities to capture P. operculella males for future development of a mass trapping technique, and a subsequent decrease in insect reproduction. The study evaluated densities of 10, 20, and 40 traps ha -1 , baited with 0.2 mg of PTM sexual pheromone, and water-detergent for captures. Results indicated that larger numbers of male PTM were captured per trap with densities of 20 and 40 traps per hectare, resulting in a significant reduction (P < 0.05) of tuber damage in these treatments compared with the control which used conventional chemical insecticide sprays

Genotype number and allelic diversity overview in the national collection of Chilean potatoes.

Chile is the origin of the Solanum tuberosum group Chilotanum corresponding to lowland tetraploid landraces. The most complete morphological description of the Chilean germplasm was published in 2008 in the Catalogue of Varieties of Native Potatoes from Chile, which describes 211 varieties. Two institutions of the Chilean government, INIA and SAG (Agricultural and Livestock Service of Chile), keep collections of 332 and 257 accessions, respectively; the varieties registered in the catalogue are included in the SAG collection. Thus, an important gap occurs between the number of varieties listed in the National Catalogue of Chile and the number of traditional varieties found in the Chilean collections of potatoes. In this work, two national collections of Chilean native germplasms (INIA-Remehue and SAG) were analysed via four microsatellite markers with the aims of (1) discriminating different genotypes in order to more accurately catalogue the current number of native Chilean varieties, (2) evaluating the diversity of genotypes potentially known with the same nomenclature by farmers, and (3) comparing allelic diversity of native germplasm with 44 commercial varieties. Of the 589 native accessions analysed, 320 different allelic phenotypes were found indicating that there are at least 320 different genotypes in the collections. Of these, 158 belonging to the INIA collection were not found in the SAG collection. These 158 new genotypes should increase the number of known Chilean varieties. As expected, different genotypes were known under the same popular name. In terms of allelic diversity, the group of commercial varieties contained a subset of the alleles within the collection of SAG and INIA-Remehue